MEKK3蛋白K391位点突变对其影响的生物信息学分析及活性鉴定

MEKK3是丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)家族的重要成员,主要参与激活c-Jun氨基末端激酶(c-Jun NH2-terminal kinases, JNK)和细胞外调节(extracellular regulated protein kinases, ERK)两条通路。利用生物信息学分析野生型MEKK3(MEKK3WT)及突变型MEKK3(MEKK3K391M)蛋白的理化性质、亲/疏水性、跨膜区、二/三级结构、相互作用蛋白等。结果表明,MEKK3K391M蛋白的稳定性增强,亲/疏水性最强位点未改变,α-螺旋、β-折叠及蛋白结合位点与MEKK3WT不同。三级结构分析显示,MEKK3K391M空间位阻增大。据GenBank提供的人源MEKK3的cDNA序列(NM_203351),扩增出野生型MEKK3WT目的基因,用重叠延伸PCR定点突变技术扩增突变型MEKK3K391M目的基因,并将其克隆至带有FLAG标签的真核表达载体pCMV-tag-2c中。DNA序列分析结果表明,MEKK3K391M基因序列成功将编码赖氨酸(Lys, K)的密码子AAG突变为编码甲硫氨酸(Met, M)的密码子ATG;免疫印迹分析显示,MEKK3WT、MEKK3K391M重组体均在PC12细胞中高效表达;MEKK3WT可以激活JNK,使JNK发生磷酸化反应,其条带灰度值明显高于对照组和MEKK3K391M组。MEKK3K391M组的P-JNK与对照组相差不大。总之,MEKK3中K391的氨基酸突变引起了蛋白结构和功能的改变,特别是三级结构的空间位阻加大,使MEKK3K391M与ATP结合能力减弱,从而无法呈递磷酸基团催化相应的底物,失去生物学活性。本研究对寻找神经系统疾病JNK通路中与MEKK3相互作用的蛋白分子、探索蛋白相互作用机制提供实验基础。     

一种失真模糊图像的无参考质量评价方法

针对现有的无参考质量评价方法对失真模糊图像不能有效评价这一现象,提出了一种针对失真模糊图像的无参考质量评价方法。该方法将结构相似度(structural Similarity,SSIM)全参考质量评价方法应用到无参考质量评价中,不仅扩宽了SSIM方法的应用范围,也解决了SSIM方法不能合理评价模糊图像质量这一缺陷。首先对失真模糊图像进行低通滤波得到参考图像,计算失真图像与参考图像的结构相似度;然后提取图像的纹理特征,计算失真图像与参考图像的纹理相似度;最后将这两个相似度指标作为输入,LIVE图像数据库提供的主观评价值(different mean objective score,DMOS)作为输出,建立一个[29 1]单隐层BP(back propagation)神经网络预测模型。实验结果表明,方法的预测结果稳定且与人的主观评价分数偏差小,Pearson相关系数(correlation coefficient,CC)和Spearman等级相关系数(rank order correlation coefficient,ROCC)均达到了0.97以上。     

基于数据互操作的建筑信息模型转换与融合方法

建筑信息模型(BIM)与三维地理信息系统(GIS)的集成,能使BIM模型得到广泛应用。主要研究在ArcGIS的支持下,将Revit创建的模型数据通过过滤、转换,集成到现有的三维GIS系统,并实现对三维模型的加载、显示、属性查询、管理等功能。将不同领域的BIM和GIS数据融合,为深化多领域之间的协同应用,以及数字城市的建设、城市规划、室内导航等应用提供技术支持。     

Warm/cold rolling processes for producing Fe-6.5wt% Si electrical steel with columnar grains

A new technical prototype for producing Fe-6.5wt% Si electrical steel sheets by directional solidification, heat treatment before rolling, warm rolling, and cold rolling was proposed in the present study. The formability of Fe-6.5wt% Si electrical steel before rolling and the reasonable process parameters of this technical prototype were obtained. Experimental results reveal that the formability of Fe-6.5wt% Si electrical steel is improved significantly under the combination of directional solidification and heat treatment before rolling. Fe-6.5wt% Si electrical steel sheets with the thickness of 0.15 mm, bright surface, few edge cracks, and high rolling yield can be successfully fabricated using this technology without any intermediate annealing during the whole rolling. The combination of directional solidification, heat treatment before rolling, warm rolling, and cold rolling can work as a new process for highly efficient and compact fabrication of Fe-6.5wt% Si electrical steel sheets.     

基于SCKF的光电跟瞄系统等效复合控制

由于高能激光武器独特的毁伤机理要求其光电跟踪瞄准系统的控制精度达到微弧度级,因此由跟踪目标加速度带来的跟踪误差已不可忽略。提出了一种速度与加速度前馈补偿以提高光电跟瞄系统跟踪精度的方法,推导了该系统加速度前馈补偿的误差系数。为获得高精度的目标运动要素,应用平方根容积卡尔曼滤波(square〖JP3〗 root cubature Kalman filter, SCKF)算法对目标进行滤波预测。在建立的等效复合控制系统中进行仿真实验,结果表明,基于SCKF前馈补偿方法相对于基于常用非线性卡尔曼滤波算法的前馈补偿方法,精度得到大幅提高。     

A hierarchical multiple criteria model for eliciting relative preferences in conflict situations

A multiple criteria decision analysis(MCDA) approach is designed for capturing the relative preference information of a decision maker involved in a conflict.More specifically,an MCDA approach based on the outranking method,ELECTRE III,is employed for ranking states or possible scenarios in the conflict from most to least preferred,where ties are allowed,for a decision maker according to his or her value system.To demonstrate how this preference elicitation methodology can be conveniently implemented in practice within the framework of the Graph Model for Conflict Resolution,it is applied to a real world water supply crisis which occurred in the town of North Battleford,located in the Canadian province of Saskatchewan.     

Comparative study on the passivation layers of copper sulphide minerals during bioleaching

The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite>bornite>pyritic chalcopyrite>covellite>porphyry chalcopyrite. The residues were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is indicated that jarosite may not be responsible for hindered dissolution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopyrite may strongly hinder copper extraction. X-ray photoelectron spectroscopy (XPS) further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu₄S₁₁, S8, and copper-rich iron-deficient polysulphide Cu₄Fe₂S₉, respectively. The ability of these passivation layers was found as Cu₄Fe₂S₉>Cu₄S₁₁>S₈>jarosite.     

Investigation on the explosive welding mechanism of corrosion-resisting aluminum and stainless steel tubes through finite element simulation and experiments

To solve the difficulty in the explosive welding of corrosion-resistant aluminum and stainless steel tubes, three technologies were proposed after investigating the forming mechanism through experiments. Then, a 3D finite element model was established for systematic simulations in the parameter determination. The results show that the transition-layer approach, the coaxial initial assembly of tubes with the top-center-point the detonation, and the systematic study by numerical modeling are the key technologies to make the explosive welding of LF6 aluminum alloy and 1Cr18Ni9Ti stainless steel tubes feasible. Numerical simulation shows that radial contraction and slope collision through continuous local plastic deformation are necessary for the good bonding of tubes. Stand-off distances between tubes (D₁ and D₂) and explosives amount (R) have effect on the plastic deformation, moving velocity, and bonding of tubes. D₁ of 1 mm, D₂ of 2 mm, and R of 2/3 are suitable for the explosive welding of LF6-L2-1Cr18Ni9Ti three-layer tubes. The plastic strain and moving velocity of the flyer tubes increase with the increase of stand-off distance. More explosives (R>2/3) result in the asymmetrical distribution of plastic strain and non-bonding at the end of detonation on the tubes.     

存在直线断层的复合模型试井曲线特征研究

鲜有文献报道井附近存在直线断层（尤其是断层位于复合油气藏内区）对试井解释的影响,因此,从渗流力学理论出发,首先建立考虑表皮和井筒储集的无限大地层两区径向复合油气藏试井解释数学模型,并通过拉氏变换对模型进行求解,再利用镜像反映原理和叠加原理研究存在直线断层的复合油气藏的无因次井底压力及压力导数曲线特征及影响因素。研究表明,当井到断层距离小于1/2内区半径时,无因次压力导数曲线将由无限作用径向流的0.5水平线变为内区受断层影响的1.0水平线和外区受断层影响的值为M₁₂水平线;当井到断层距离大于1/2内区半径时,无因次压力导数曲线将由无限作用径向流的0.5水平线变为反映外区特征的值为M₁₂水平线和反映外区受断层影响的值为M₁₂的水平线。     

黄河三角洲土壤动物群落多样性和相似性

本文对黄河三角洲土壤动物群落多样性和相似性进行系统分析,探讨成土年限、植被类型对土壤动物群落演替的影响．研究结果表明,黄河三角洲土壤环境条件恶劣,土壤动物种类贫乏,且优势类群明显,群落异质性差,土壤动物群落的多样性较低,多样性指数不及最大多样性指数的二分之一．农田生态系统则因为人类的活动而改善了土壤环境,土壤动物的种类和数量均有所增加,多样性较高．11个样点、3个年代三角洲或6种植被类型之间土壤动物群落相似性较高,土壤含盐量是影响土壤动物最为重要的环境因子．随成土年限或植物群落演替,土壤动物群落在较高分类阶元上未能表现出明显的演替过程,有必要对土壤动物的分类进一步细化．